Vayikra 12:1 And God spoke to Moshe saying:2 Speak to the children of Israel saying, "A woman when she will cause to sow and give birth to a male, she will be ritually impure for seven days; as the days of the infirmity of her menstrual cycle she will be ritually impure. 3 And on the eighth day the flesh of his foreskin will be circumcised.

A bit of context: The Torah here is talking here about issues regarding ritual purity and impurity, tumah and taharah (טומאה וטהרה). This parsha in fact mainly deals with special issues of tumah and taharah which are associated specifically with the woman who gives birth.

However, I am not interested in that bit -- at least not yet. I just want to understand two basic things:

1) What does the word tazria תזריע mean? (I translated it literally as cause to sow --awkward but we'll deal with it soon)

2) Why does the Torah need to mention the phrase ki tazria כי תזריע at all?

To clarify this second question first: If we read the second verse without the phrase ki tazria at all, it would seem to give us the same basic information, namely that if a woman gives birth to a male child she will become ritually impure and that he will need a bris in eight days.

What does this ki tazria tell us, add for us, that it was so important for the Torah to mention it?

To try to answer the first question, let's look at what I believe is the only other instance of the word form tazria תזריע in Tanach.

Tazria derives from the same root as zera זרע , meaning seed--the verb form zara means to sow. Tazria is a hif'il form which, for all you Hebrew grammar buffs, and even those of you who aren't, is a causative form. What that means is that given the basic root means to sow, the hif'il form of the word would mean 'to cause to sow.' Or at least it could mean that. It implies at minimum that this woman is causing something to happen to seed which in this context would likely be sperm.

So now that I realize that I did not pay attention to may time management and it is nearly shabbat, I will leave you to figure out where else we see this causative form in the Tanach. BIG HINT: If you start at the beginning of the Torah you won't have to look very far.